You can not Capture with the Media Stores.
Where are you getting the image from that you would like to have it on the USB after you have it in the Media Channel? Is this from XPression?
In XPression while on the Sequencer you can right click on the item and "export" it to Images. There you can select if it is a TGA sequence (you built it as a motion graphic) or just a single frame. Then once exported you can FTP to the CrossOver (use the user/password login credentials -- yes they are user and password) you will see the USB as an available folder. You can now navigate the USB and drag and drop the files to it.
Les
#CrossOver